Have you tried HeinLein Supply?. They carry Modine parts. Replacing
the squirrel cage can't be that hard to do. I've done it on clothes
dryers, etc. The unit should have come with an exploded drawing and
parts list; with those, a little common sense and some basic tools,
you should be able to do the job.

If you attempt it, be sure to shut off the current at the breaker box
first.

J. Del Col